We propose to investigate the metabolism of fibrin in the atheromatous/fibrous plaques in the aorta of victims of accidents and sudden death in our surgery population to ascertain whether fibrin metabolism is abnormal in those which are atherosclerotic. Controls will consist of aortas showing no overt plaque formation as well as internal controls from normal tissue in those with plaques. Parameters to be measured in plaque include fibrin (measured as fragment D after plasmin digestion), factor XIII, a lipoprotein profile on cytoplasm of aortic intima, plasmin, plasminogen, Alpha 2 macroglobulin, Alpha 1 antitrypsin. With the exception of the lipoprotein and factor XIII these parameters will be assayed using immunological techniques. These parameters were chosen to determine if there is a correlation between a possible hyper-coagulatable state or hypofibrinolysis and the number and size of fatty streaks and atheromatous/fibrous plaques. The data will be analyzed using multivariate analysis. We are especially interested in the levels of Factor XIII (Fibrinoligase) in plaques and fatty streaks in those with atherosclerosis compared with normal controls.